The unifying hypothesis for this grant application is that LPA2 agonists have the potential for therapy of cholera and other types of enterotoxin-induced secretory diarrhea. Thus in this renewal application we propose to develop a physiologically relevant human intestinal stem cells (enteroids) to study CFTR-dependent fluid secretion and develop assays to demonstrate and identify LPA2 receptor specific small molecule agonists. LPA2 dependent inhibition of CFTR requires adenylate cyclase 6 (AC6) suggesting that AC6 is part of the CFTR-NHERF2-LPA2 complex. Two hypotheses will be tested: Specific Aim 1: To test the hypothesis that LPA2 agonists attenuate CTX-induced and CFTR- dependent fluid secretion in human intestinal stem cells (spheroids and enteroids), and mitigate diarrheal symptom Specific Aim 2: To test the hypothesis that adenylate cyclase 6 (AC6) exists in the macromolecular complex of CFTR-NHERF2-LPA2 in human intestinal epithelial cells and that AC6 plays an important role in modulating LPA2-dependent inhibition of CFTR channel function that can be therapeutically relevant in targeting LPA2 in controlling secretory diarrheas. The proposed study is highly significant because (a) it addresses a deadly disease; (b) it has clinical relevance and implications; (c) it is a multidisciplinary project coves basic biomedical studies, high throughput assay development, and sets a stage for future drug discovery.